I think he's a solid 2. He fails to meet innings pitched requirements for leaders boards by 2.1 innings. (159.2, 162). If you drop the filter to 100 IP (so as to avoid manipulation to include *just* him) he is 33rd in baseball in fWAR (2.9). (I could have gotten him as high as 27th in baseball by setting the innings limit to 150)
Above Rea, Shota, Taillon, Horton and not far behind Boyd (22nd at 3.4). So in baseball, a SOLID #2. On this team, a depending on performance, a 2 or 3. (not including Steele).
But this team does not lack solid pitchers. Heck even Ben Brown was top 100 fWAR last year, above Shota. This team lacks an ACE. Maybe Horton becomes that. Maybe Steele comes back better than ever, but I'd rather shoot for the moon with Imai than another solid, get-us-to-the-playoffs-only-to-bow-out-in-round-2 guy.
The floor is high. now raise the ceiling.